A perturbation technique for flow-induced vibration control

Li Cheng, Y. Zhou, M. M. Zhang

Research output: Journal article publicationConference articleAcademic researchpeer-review

Abstract

This paper presents a novel technique to perturb the vortex shedding from a bluff body and subsequently suppress the flow-induced structural vibration. The essence of the technique is to create a local perturbation on the surface of a bluff body using piezoelectric actuators. Experiments were carried out in a wind tunnel. A square cylinder of a height h, flexibly supported on springs at both ends, was allowed to vibrate only in the lift direction. Three actuators were embedded underneath one side, parallel to the flow, of the cylinder. They were simultaneously activated by a sinusoidal wave, thus causing the cylinder surface to oscillate. The structural displacement Y and flow velocity u were simultaneously measured using a laser vibrometer and a single hot-wire, respectively. When the vortex shedding frequency fssynchronized with the natural frequency of the dynamic system, Y was estimated to be about 0.08h. This displacement collapsed to 25% once the actuators were excited at a normalized frequency fh/U∞= 0.1 (U∞is the free-stream velocity) and amplitude of 0.028h. The laser-illuminated flow visualization captured drastically weakened vortices shed from the cylinder. Spectral analysis of the Y and u signals points to the fact that the imposed perturbation has altered the spectral phase at fsbetween fluid excitation and structural vibration from 0 to π, and meanwhile decreased the spectral coherence at fsfrom 0.65 to 0.15. It is expected that the perturbation technique presently investigated will have an important role to play in the flow-induced vibration control, especially with the active control element assimilated into the system.
Original languageEnglish
Pages (from-to)491-500
Number of pages10
JournalAmerican Society of Mechanical Engineers, Applied Mechanics Division, AMD
Volume253
Issue number1
DOIs
Publication statusPublished - 1 Dec 2002
Event2002 ASME International Mechanical Engineering Congress and Exposition - New Orleans, LA, United States
Duration: 17 Nov 200222 Nov 2002

ASJC Scopus subject areas

  • Mechanical Engineering

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